Determination of Arsenic in Edible Oils by Direct Graphite Furnace Atomic Absorption Spectrometry

SYR-SONG CHEN*, CHIEU-CHEN CHENG AND SHIN-SHOU CHOU

Bureau of Food and Drug Analysis, Department of Health, Executive Yuan No.161-2, Kunyang St., Nangang District, Taipei City 115, Taiwan (R.O.C.)

(Received: August 28, 2001; Accepted: January 27, 2003) 

ABSTRACT

   A direct analytical method of arsenic content in edible oil with graphite furnace atomic absorption spectrophotometer was studied. Edible oil was diluted with n-heptane followed by the determination of arsenic with Zeeman graphite furnace atomic absorption spectrophotometer and transverse heated graphite atomizer (THGA). The arsenic organic AAS standard solution was used as calibration standard, and bis (benzonitrile) dichloro palladium solution was used as a matrix modifier. The results showed that the optimal ashing and atomizing temperatures were 1200℃ and 2300℃, respectively. The detection limit was estimated to be 0.010 ppm, and the percentages of recovery for the spike of 0.05, 0.10 and 0.20 ppm arsenic to salad oil, fish oil, palm oil, and lard were 91.2~94.3%, 94.7~95.6%, 94.2~96.7% and 93.3~94.1%, respectively. With the use of this method, thirty edible oils were analyzed and the arsenic contents were found to be below the detection limits.
 
Key words: graphite furnace atomic absorption spectrophotometer (GFAAS), arsenic, edible oils